The application generally relates to a method for forming an electrophotographic imaging member and, more particularly, to a method for forming an imaging member which includes a photoconductive layer comprising elemental selenium and a charge carrier transport material dispersed within an electrically insulating binder material.
The formation and development of images on an imaging member of photoconductive materials by electrostatic means is well known. The best known of the commercial processes, more commonly known as xerography, involves forming an electrostatic latent image on the imaging layer of an imaging member by first uniformly electrostatically charging the surface of the imaging layer in the dark and then exposing this electrostatically charged surface to a light and shadow image. The light struck areas of the imaging layer are thus rendered relatively conductive and the electrostatic charge selectively dissipated in these irradiated areas. After the photoconductor is exposed, the latent electrostatic image on this image bearing surface is rendered visible by development with a finely divided colored electroscopic powder material, known in the art as "toner". This toner will be principally attracted to those areas on the image bearing surface having a relative polarity opposite to the charge on the toner and thus form a visible powder image. The developed image can then be read or permanently affixed to the photoconductor in the event that the imaging layer is not to be reused. This latter practice is usually followed with respect to the binder-type photoconductive films where the photoconductive insulating layer is also an integral part of the finished copy.
In so-called "plain paper" copying systems, the latent image can be developed on the imaging surface of a reusable photoconductor or transferred to another surface, such as a sheet of paper, and thereafter developed. When the latent image is developed on the imaging surface of a reusable photoconductor, the developed image is subsequently transferred to another substrate and then permanently affixed thereto. Any one of a variety of well-known techniques can be used to permanently affix the toner image to the transfer sheet, including overcoating with transparent films and solvent or thermal fusion of the toner particles to the supportive substrate.
In the most popular of the xerographic systems the imaging member comprises a photoconductive insulating layer of amorphous selenium. There are also known in the art photoconductive layers wherein selenium and a charge carrier transport material capable of transporting at least one species of charge carrier are dispersed throughout an electrically insulating polymeric binder material.
Chu et al have disclosed a method for forming such a member in U.S. Pat. No. 3,994,791. In this method an organoselenium precursor compound is dispersed in a polymeric binder matrix and the compound is decomposed thereby causing elemental selenium to be deposited throughout the matrix. According to the disclosed method the polymeric binder matrix may include or be made up of a charge carrier transport material which is capable of transporting at least one species of charge carrier.
In well-established technical fields such as xerography new techniques are proposed for the formation of known articles. The present invention is directed to a novel method for the formation of an electrophotographic imaging member.